Dictyostelid cellular slime molds in canopy soils of tropical forests

The occurrence and distribution of dictyostelid cellular slime molds (CSM) in the mantle of dead organic matter (literally a canopy soil") at the base s of large epiphytes were studied in the Luquillo Experimental Forest of no rtheastern Puerto Rico. CSM were isolated from 18 of 50 samples collected f rom this microhabitat, and four different species were recovered. Dictyoste lium purpureum was the single most abundant species and represented almost half (48%) of all clones isolated during the study. Total densities (clones /g) averaged only 38 in the five forest types examined, bur densities > 75 were recorded for two forest types. Relative abundance of CSM in canopy soi ls of the five forest types followed the same general pattern displayed by these organisms in forest floor litter, bur a particular species was not ne cessarily common to both microhabitats in a given forest type.